The auto check option highlights
obvious mistakes; for example, two 1's in the same row. Note that
this (intentionally) does *not* verify that the number is correct,
only that it is not illegal with respect to the current state of the
grid illegal.

Select auto advance to have the
highlighted cell advance on number entry.

Select auto sweep to automatically
update the options in each cell as you input numbers.

The title box allows you to name the
puzzle for the printable page. Note that this isn't the way to
retrieve puzzles from the archive.